Initial detonating agent



UNITED STATES WALTER O. SNELLING, OF ALLENTOWN, PENNSYLVANIA.

INITIAL DETONATING AGENT.

No Drawing.

To all whom it may concern Be it known that I, WALTER O. SNELLING, a citizen of the United States, residing at Allentown, in the county of Lehigh and State of Pennsylvania, have invented certain Improvements in Initial Detonating Agents, of which the following is a specification.

My invention relates to improvements in detonating agents, and more particularly to an improved method for the preparation of lead azid and like initial detonating compounds.

Lead azid is a highly explosive body which may be obtained by causing sodium azid or other alkali azid to react in aqueous solution with a soluble salt of lead. It is commonly prepared by dissolving sodium azid in water, and adding to the solution so prepared a solution of lead nitrate, the following reaction occurring:

As soon as the solutions of lead nitrate and sodium azid are mixed together, lead azid precipitates in the form of a crystalline powder. The temperature and concentration of the solutions before mixing, and the thoroughness and rapidity of mixing have been recognized to have an effect upon the size of the resulting crystals of lead azid, and the sensitiveness of the resulting crystals has been found to be a factor of the crystal size, large crystals being much more sensitive than smaller crystals. I

Frequent accidents in the handling of lead azid have been considered to be due to occasional crystals larger'in size than the average being formed, these large crystals being recognized to be unduly sensitive, and quite liable to be exploded by minor shocks and blows. In spite of the many efforts which previous workers have made to devise means' for producing fine crystals of lead azid only, it has been found to be almost impossible to insure freedom from occasional larger crystals when the azid is made on a commercial scale by the methods heretofore known.

I have discovered a means of avoiding the formation of large crystals of lead azid, and of preparing crystals of this material of much smaller size, and of much greater uniformity of size, than has hitherto been possible.

I have found for example, that if I dis- Specification of Letters Patent.

Patented Sept. 21, 1920.

Application filed May 6, 1920. Serial N0. 379,292.

solve a water-soluble azid in a solution of glue, instead of dissolving this material in water, and if I similarly dissolve lead nitrate or other water-soluble salt of lead in a solution of glue, instead of in Water, on mixingthe two solutions together I obtain crystals of lead azid which are extremely uniform. in size, and which are much smaller than when aqueous solutions of sodium azid and lead nitrate are employed.

Other colloidal materials may be employed instead of glue with similar effect, the influence of the colloid being to hinder the formation of crystals, and to cause the crystals which form to be of smaller size. By using concentrated colloidal suspensions as solvents for both the sodium azid and the lead nitrate I can obtain my lead azid as a mud, in which the crystals are extremely minute, while by employing less concentrated colloidal suspensions 0r solutions, or by only using such colloidal suspension or solution as solvent for one of my reacting materials, I can obtain fine crystals of uniform size, which, although much larger than the crystals obtained when concentrated colloidal suspensions are employed, are still much smaller than the crystals which are obtained when only aqueous solutions are used.

Although I have described my invention as applied to the preparation of lead azid, it is evident that it may be also used in the preparation of other highly explosive fulminating compounds, and accordingly it is not to be strictly limited to the example as set forth, but may be broadly applied to chemical reactions in which two reacting substances in solution are mixed. .together to form by chemical interchange a highly explosive substance which is, dangerously sensitive when present in large or stals. It will be evident that many mo ifications may be made without departing from the spirit and scope of my invention and it is therefore to be understood that no limitations are to be imposed upon my invention unless indicated in the appended claims.

I claim:

1. The rocess which comprises forming crystals 0 an initial detonatmg agent in a liquid containing a suspended COllOld.

2. In the manufacture of initial detonating agents of crystalline nature, the process of preventing the formation of large or stals which comprises causing the reaction producing. such substances to take place in the presence of a colloid body in suspenslon.

3. In the preparation of an azid of a 5 heavy metal, the process which comprises causing an alkali azid and a soluble salt of the heavy metal to react in thepresence of a colloid.

4. In the manufacture of lead azid, the 10 process which comprises causing an alkali azid and a soluble salt of lead to react in a solution of glue.

In testimony whereof, I have hereunto subscribed my name this 4th day of May,

WALTER O. SNELLING. 

